vercel deploy success but access web error Nextjs 14 undici wrong verssion

ONLINECAST

2 min read

·

31-08-2024

15

0

Share

Next.js 14 Deployment Headache: Vercel Success, Website Error

You've successfully deployed your Next.js 14 application to Vercel, but when you try to access it, you're greeted with an error: "A server-side exception has occurred." This is a frustrating situation, especially when local development goes smoothly. This article will investigate the common cause – incorrect undici version – and guide you through the fix.

Understanding the Problem

Next.js 14 introduces the undici package for its fetch implementation. This package is responsible for making HTTP requests, and its compatibility with your Node.js version is crucial.

The Root Cause: Undici and Node.js Version Mismatch

The error you're encountering is likely due to a version mismatch between your Node.js version (20.x in your case) and the undici package. The undici package might be expecting specific Node.js features or behaviors that are unavailable in your Node.js environment.

Troubleshooting and Solution

Here's how to troubleshoot and fix the undici version problem:

1. Inspect the Error Message: Pay close attention to the server-side exception details. The error message will often point to undici or a related package.

2. Verify undici Version: Check your package.json file. Look for the undici package and its version number. If the version is outdated, updating it can solve compatibility issues.

3. Upgrade Node.js: If you're still facing problems, consider upgrading your Node.js version to the latest LTS (Long-Term Support) release. Vercel often uses the latest LTS version.

4. Vercel Configuration: Double-check your Vercel project settings. Ensure that the Node.js version specified in Vercel aligns with your local development environment.

Code Example (package.json):

{
  "dependencies": {
    "undici": "^5.1.0" 
  }
}

Important Considerations:

• Always Test: After making any changes to your package.json or Node.js version, ensure you run npm install or yarn install to install any necessary packages. Always test your application thoroughly before deploying.
• Vercel Support: If you're still facing issues, consult Vercel's documentation or contact their support team for assistance.

Additional Tips:

• Dependency Tree: Use tools like npm ls or yarn why to analyze your dependency tree and identify any conflicting versions or outdated packages.
• Environment Variables: Make sure your environment variables are set correctly in both your local development environment and on Vercel.

Conclusion

Next.js 14's reliance on undici makes version compatibility essential for a smooth deployment. By understanding the root cause and following the troubleshooting steps outlined above, you can effectively resolve this common deployment issue and get your Next.js application running on Vercel.